In many systems, it is necessary to quickly and reliably amplify analog voltage signals in order to properly interface analog circuitry with digital logic circuitry. This need frequently arises when the analog voltage signal is formed by a differential voltage between two voltage signals. In that case, a sense amplifier may be used to amplify the difference between the first and second voltage signals to achieve a proper interface with digital logic circuitry. For example, if the first voltage signal is positive relative to the second voltage signal, then the sense amplifier amplifies the difference between the two voltage signals, so that the amplified first voltage signal has a digital logic value of "1" and the amplified second voltage signal has a digital logic value of "0". Alternatively, if the first voltage signal is negative relative to the second voltage signal, then the sense amplifier amplifies the difference between the two voltage signals, so that the amplified first voltage signal has a digital logic value of "0" and the amplified second voltage signal has a digital logic value of "1".
In order to properly amplify such a differential voltage, sense amplifiers typically require a minimum difference between the two voltage signals and a minimum time period for performing the sense amplification process, while achieving a specified reliability of the digital logic outputs. If a difference between the two voltage signals is too small, or if a time period allowed for performing the sense amplification process is too short, then the sense amplifier might not fully amplify the differential voltage within the allowed time period. It is also possible that the sense amplifier might improperly amplify the differential voltage, so that the amplified voltage signals have digital logic values that are inverted from their proper states.
It is desirable to reduce a minimum difference required between two voltage signals forming a differential voltage and to reduce a minimum time period required for performing the sense amplification process, while still achieving a specified reliability of the digital logic outputs. By reducing the minimum difference and the minimum time period, system power is saved, and system speed is increased.
Thus, a need has arisen for a method and circuitry for sense amplification, which reduces a minimum difference required between two voltage signals forming a differential voltage, and which reduces a minimum time period required for performing the sense amplification process, while still achieving a specified reliability of digital logic outputs.